Dooseop Choi

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Based on the observation that low-frequency DCT coefficients of an image are less affected by geometric processings, we propose a new blind MPEG-2 video watermarking algorithm robust to camcorder recording. The mean of the low-frequency DCT coefficients of the video is temporally modulated according to the information bits. To avoid watermark’s drift into(More)
This paper presents a blind digital video watermarking scheme, which is especially robust to camcorder recording attacks and also to a variety of common video processing and geometric distortions. Using the fact that nearby frames of a video sequence are quite similar, the method embeds the watermark by temporal modulation of the frames. The watermark(More)
Most commercial iris recognition systems use infrared or near-infrared cameras to capture the iris images because they show rich and complex textures that can be used to identify a person. This paper presents the design and implementation of a multispectral iris acquisition system that can efficiently capture and store iris images exposed under different(More)
This paper proposes a new approach to motion vector field smoothing for block-based motion-compensated frame interpolation (MCFI). Based on the assumption that an observed motion vector field, which is the result of a block-based motion estimation (BME), is a degraded version of the true motion vector field, we calculate the maximum a posteriori (MAP)(More)
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